1. Field of the Invention
This invention relates firearms and more particularly to firearm barrels with rifling.
2. Description of the Related Art
A rifle typically includes a chamber on the breach end of a rifle where an ammunition cartridge is placed. The cartridge typically includes a cylindrical case filled with primer and gun with a bullet located at its opposite open end, called the mouth. The case is held in the chamber so that when the trigger is pulled, a firing pin contacts the head of the cartridge causing the primer and gunpowder to ignite and force the bullet out the mouth.
Located immediately adjacent to the chamber is a short narrow throat slightly larger in the diameter than the bullet. The throat includes a short cylindrical body with a single, short tapered step formed at its forward end that gradually narrows and communicates with the rifle bore. Formed on the inside surface of the tapered step and extending the entire length of the rifle bore is at least one engraving groove that creates rifling on the sides of the bullet. When a cartridge is discharged, the bullet travels through the free bore, into the tapered step and then into the rifle bore. While traveling through the throat, the bullet is forced into coaxially alignment with the rifle bore and undergoes engraving.